Containers capable of dispensing contents stored in the containers are known in the art. In certain applications, a dispenser may have a membrane that is selectively rupturable wherein upon rupture, a flowable substance can be dispensed from the container. For example, U.S. Pat. Nos. 5,490,746 and 5,664,705 disclose containers having rupturable membranes. The disclosed membranes, however, are made rupturable via score lines in the membranes. As are known in the art, score lines are weakened areas, typically formed by the removal of material. The membranes are ruptured by creating hydraulic pressure within the container where the membranes rupture along the score lines. Furthermore, in the membrane disclosed in U.S. Pat. No. 5,664,705, portions of the membrane overlap one another and the membrane is not integral with the dispenser but rather separately affixed to the dispenser wall. The use of score lines provides less control over the manner in which the membrane will rupture. In addition, separately attaching a membrane to a container adds to the complexity of the manufacturing process and cost. In other embodiments, the membrane may be generally flat or planar and have a weld seam that provides for the rupturability of the membrane. Limitations in the structural configuration of the prior art rupturable membranes can restrict the operability of the membrane and the type of flowable substances that can be suitably contained and dispensed from the container.
The dispensers having rupturable membranes are often formed in a plastic injection molding process. Various types of thermoplastic materials can be used. For example, the plastic material could be polyethylene or polypropylene. The various types of thermoplastic materials often limit the type of flowable materials that can be contained and dispensed from the dispenser because of chemical incompatibilities or other constraints. For example, one potential particular use for the dispenser is containing and dispensing topical antiseptics for surgical preparation of patients, sometimes referred to as surgical prep solutions. One such antiseptic is chlorohexadine gluconate (CHG) and is typically contained in glass ampoules because of difficulties in adequately storing CHG material in thermoplastic containers. Attempting to store CHG material in a thermoplastic container has proven to be unworkable because the CHG material reacts unfavorably with the thermoplastic material and no longer properly functions as an antiseptic as it loses its strength. For example, it has been found that potential shelf-life of CHG material stored in a thermoplastic container is too short to be commercially feasible and acceptable in a medical setting. The material may also permeate through the dispenser material. Because storing CHG in glass ampoules presents a separate set of problems (e.g., glass shards, premature opening of containers), a thermoplastic-based dispenser capable of containing and dispensing a CHG material would be desirable. Such a container would also be desirable for use with other types of surgical prep solutions or other acetone or alcohol-based solutions. Challenges have also been experienced with thermoplastic-based dispensers used to container acetone-based solutions or solutions with high concentrations of alcohol. Such solutions will leach through the dispenser materials including any weld seams incorporated into the rupturable membrane. Further challenges have been experienced in that the thermoplastic material of the dispenser must also be capable of forming a member that can be manually ruptured by a user. For example, a dispenser made from a particular thermoplastic may possess good chemical resistance properties but be too stiff to allow a user to fracture or rupture the dispenser via finger pressure.
While such containers according to the prior art, provide a number of advantageous features, they nevertheless have certain limitations. The present invention is provided to overcome certain of these limitations and other drawbacks of the prior art, and to provide new features not heretofore available. A full discussion of the features and advantages of the present invention is deferred to the following detailed description, which proceeds with reference to the accompanying drawings.